PROJECT SUMMARY/ABSTRACT Microbes rarely live alone. In the ocean, the soil, and the human body, microbes live within complex, multi-species communities. Yet, due to complexity of these communities, it is often extremely difficult to understand how they work. To address this challenge, my lab has taken the approach of developing simplified microbial communities as model systems. The goal of our work is to understand the basic mechanisms that shape microbial communities and to identify general principles of community formation. Our previous work has focused on establishing an experimental framework for building, manipulating, and studying simple, culturable, systems based on communities from fermented foods in the lab. We are now working to capitalize on this experimental system to identify molecular mechanisms that are responsible for the formation of a microbial community, and to better understand what happens when this process goes wrong. We will be drawing on our expertise in genetics, genomics, and microbial interactions to push forward the field of microbiome research through the use of a simple model system.